# -*- coding: utf-8 -*-
'''
爬虫url管理器
'''
class UrlManager(object):
    def __init__(self):
        self.new_urls=set()
        self.old_urls=set()

    def add_new_url(self,url):
        if url is None:
            return
        if url not in self.new_urls and url not in self.old_urls:
            self.new_urls.add(url)


    def add_new_urls(self,urls):
        print urls
        if urls is None or len(urls) == 0:
            return
        for url in urls:
            self.add_new_url(url)


    def has_new_url(self):
        return len(self.new_urls) != 0

    def get_new_url(self):
        new_url =self.new_urls.pop() #获取并移出
        self.old_urls.add(new_url)

        return new_url

